# Can anyone make any sense out of this question: Tree MEX

Hi,

I tried my best to understand this question TREEMX, but couldn’t get it what is exactly asked in this question.

Solving it is a completely different thing.

When I’m writing this post, total submissions done on this questions were 9, with an accuracy of 11%, which translates to only 1 person that I suspect was done the author himself.

Any help and walk over the example input / output would be helpful.

• The question was NOT set by me, it was set up by Moscow Workshops ICPC and since their setters had no codechef account, it shows name of admin who imported the problem and customised it to codechef systems.
• `total submissions done on this questions were 9, with an accuracy of 11%, which translates to only 1 person that I suspect was done the author himself.` I dont see any correct submission on it. Plus, why not yourself go to all submission and verify instead of posting your so called “suspicion”
• The question seems clear to me and well, I’d suggest to try again because questions in contests are also of similar format.
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Thanks for clarifying that. Apologies. Probably I should not have highlighted into my question anything about the author and the submissions stats. all the response were highlighted around that, except from addressing the crux of what was asked: explanation.

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Consider a permutation P=(v_i,v_j,_v_k...). Set A_i=MEX(u_{i1},u_{i2},u_{i3}....) where (u_{i1},u_{i2},u_{i3}....) are neighbors of corresponding v_i in P. Its obvious that we can get same A for multiple permutations P. Find number of distinct A sequences possible over all n! P.

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Does anyone know how to do this problem??

I am trying to understand this problem can someone pls help me ?
So as per the problem statement eg
P(2,3,1). A§ = (1,0,1) - >But i dont understand how they got this. As per my understanding:
-First assign all values to -1
A = (-1, -1, -1)
-Now taking v1 from P i.e 2. As 2’s neighbours are 1, 3 their Ai is -1, -1
So MEX(-1,-1) => 0

Is this approach correct ?

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